Tire sidewalls are often coated with a protective paint layer, particularly tire sidewalls that have a coloring other than that of the typical black tire. Generally, these sidewalls have a white coloring. White sidewall tire protective paints should have good stain and humidity resistance in order to protect the white sidewall during storage and transportation before application to a vehicle.
The carbon black reinforcement in rubber tires, typically imparts a black color to the tire. In order to produce a different color on a part of the tire, the carbon black is generally replaced with another pigmenting agent. For example, the white sidewalls of a tire contain TiO.sub.2 and no carbon black. Other compounding agents used in rubber formulations, such as amine based compounds, can stain or discolor the white sidewall area. Moreover, during storage, anti-ozonants, antioxidants, and oils from the treads of black sidewalls of adjacent tires, often migrate and stain the white sidewall. This becomes a particular problem in high humidity conditions.
Also, under relatively high humidity conditions, conventional coatings, such as polyvinyl alcohol (PVA), or other coatings known to the art and to the literature, can soften. This softening allows the coating to scuff easily, and abrade away and can occur by the tire merely rubbing against another tire, thus leaving the side-wall unprotected.
Rosthauser U.S. Pat. No. 4,925,885 discloses aqueous compositions for use in the production of crosslinked polyurethanes.
Patitsas U.S. Pat. No. 4,911,218 relates to a composition comprised of polyvinyl alcohol coating and at least one water insoluble particulate organic or inorganic material having a plate like structure for use on at least one side of a rubber tire.
Henning U.S. Pat. No. 4,857,565 discloses a process for the continuous production of aqueous polyurethane dispersions and their use as a coating composition or as an adhesive.
Buethe U.S. Pat. No. 4,287,039 discloses an aqueous radiation-curable binder composition containing a water-dispersible prepolymer containing polymerizable carbon-carbon double bonds, and a dispersion aid.
Kinoshita et al. U.S. Pat. No. 4,208,311 discloses an aqueous urethane diamine dispersions forming coating compositions with aqueous diepoxide dispersions, containing polyoxyethylene aryl- or lauryl ether emulsifiers.
Japanese Patent 58132051 discloses a thermosetting urethane emulsion paint, particularly for coating non-flat surfaces comprising a) thermosetting urethane emulsion paint; b) a boiling point organic solvent; and optionally c) an aromatic organic solvent co-boiling with water; and/or d) a viscosifier.
Japanese Patent 53126047 discloses a method comprising adding powders to aqueous resin emulsions, mixing them and forming many bubbles in the mixtures, and coating base materials with the paints.
European Patent 307775, to Kruse, discloses a water-dispersible modified polyurethane thickener that increases the high shear viscosity of aqueous compositions while providing acceptable flow and levelling characteristics.
EP Patent 7032 discloses a thermosetting aqueous nonionic dispersion for spray-coating that contains a hydroxyl group-containing polymer, a masked polyisocyanate and an auxiliary dispersant. The dispersions are used for lacquering metals, particularly as car lacquers and also coil coatings, and can be sprayed on as primers or filler coatings.